Physiology of Taste and Smell Flashcards
What are the organs of taste?
Taste buds
What two types of cells do taste buds contain?
Sensory receptor cells
Support Cells
What structure are the arranged like?
Slices of an orange
Taste receptors have a life span of…
10days
When they die, taste cells are replaced by from where?
Basal cells in the taste buds
Taste buds are mainly contained in which areas?
Tongue
Pharynx
Palate
Epiglottis
The majority of taste buds are where
the papillae on the dorsum of the tongue
Name the four types of papillae in the tongue
Vallate
Filiform
Fungiform
Foliate
Which of the papillae contain taste buds? Which hold the majority of taste buds
Vallate
Fungiform
Foliate
Binding of a tasting causes the cells to alter in what way?
The ionic channels become altered and depolarise the receptor potentials - receptor potentials then initiate the AP in the afferent nerves
The cranial nerves conduct the signal to which area of the brain? through which other areas do they pass?
The cortical gustatory area
They pass through the brainstem and thalamus
Afferent taste fibres reach the brainstem via the ….
Facial nerve
Glossopharyngeal nerve
Vagus nerve
Afferent taste fibres pass through the facial nerve in the ______ via its _______ branch
The facial nerve supplies taste in the anterior 2/3rds of the tongue via its chorda tympani branch
Afferent taste fibres pass through the glossopharyngeal nerve in the ______
posterior third of the tongue
Afferent taste fibres pass through the vagus nerve from the ______ and ______
Afferent taste fibres pass through the vagus nerve from the pharynx and epiglottis
Name the 5 primary tastes we can sense and what tastant stimulates them
Salty - chemical salts especially NaCl
Sour - acids (H+ ions)
Sweet - configurations of glucose
Bitter - diverse group including alkaloids, poisons and toxic plant derivatives
Umami (meat/savoury) - amino acids especially glutamate
What is ageusia?
Loss of taste
Name a few causes of ageusia
nerve damage Local inflammation (e.g. glossitis/radiation or tobacco induced inflammation) Some endocrine disorders
What is Hypogeusia
reduced taste function
Name a few causes of Hypogeusia
Chemotherapy
Medications
What is dysgeusia?
Distortion of taste
Name a few causes of dysgeusia
Many causes including: Glossitis Gum infection Tooth decay reflux URTI medications Neoplasm chemotherapy zinc deficiency and many many more
Where are the cells that detect smell?
the olfactory mucosa in the dorsal roof (ceiling) of the nose
Name the three cells contained in the olfactory mucosa and their function
Olfactory receptor cells - detects odourants
Support cells - metabolic and physical for the olfactory receptor cells
Basal cells - mucous secreting cells
